msi: introduce ARCH_SUPPORTS_MSI Kconfig option (rev2)

Allows architectures to advertise that they support MSI rather than listing
each architecture as a PCI_MSI dependency.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index e19185d..3b71f97 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -14,6 +14,7 @@
 	select PCI if (!IA64_HP_SIM)
 	select ACPI if (!IA64_HP_SIM)
 	select PM if (!IA64_HP_SIM)
+	select ARCH_SUPPORTS_MSI
 	default y
 	help
 	  The Itanium Processor Family is Intel's 64-bit successor to